In wireless communications systems, when schedule based access is used to allocate physical radio resources to mobile stations (MSs), the scheduler at the base station (BS) requires some critical information. For example, an uplink scheduler needs to know which MS needs PHY resources and how much and how urgent the MS needs the PHY resources. For another example, a downlink scheduler may need to know which modulation and code rate should be applied to the PHY resources for sending data to an MS. Such systems include present and future Institute for Electrical and Electronic Engineers (IEEE) 802.16e, LTE and 802.16m standards.
In the uplink (UL), one mechanism is needed for the MS to send to its serving BS both bandwidth request (BWREQ) indicators and BWREQ information to describe how the data should be scheduled to its serving BS. Previously, (e.g. IEEE802.16e or LTE) a MS sends the bandwidth indicator first and if the indicator is captured by the BS, in the next step the BS may grant PHY resources for the MS to send the bandwidth request. In LTE, an UL bandwidth request indicator (or schedule request in LTE terminology) is sent in a periodically allocated PHY resource (refer to as polling hereafter).
Polling has a major drawback when the bandwidth request rate is low. For example, in a typical Voice over Internet Protocol (VoIP) case, 0.4 BWREQ/user/second is needed to tell the BS a UL talk spurt starts. In order to meet the delay requirement within 5 ms, a MS needs to have one periodical PHY resource every 5 ms no matter if it has a bandwidth request to send or not. Another drawback is the large latency. Namely, the bandwidth request is sent after receiving a correct bandwidth indicator capture and successful PHY resources allocation for the bandwidth request.
Thus, a strong need exists for techniques for quick access channel information loading in wireless networks.
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